SENSORY NEURON TOXICITY TRIGGERED BY ANTICANCER DRUGS IS COUNTERACTED BY EXTRACELLULAR VESICLES DERIVED FROM ADIPOSE-DERIVED MESENCHYMAL STEM CELLS

D’Aprile C¹, Naghshbandieh A^1,3, Fabbro V¹, Turano E², Scambi I², Virla F², Caprioli M², Mariotti R², Scuteri A¹ and Meregalli C¹ | ¹Experimental Neurology Unit and Milan Center for Neuroscience, School of Medicine and Surgery, University of Milano-Bicocca, Italy; ²Department of Neuroscience, Biomedicine and Movement Sciences, University of Verona, Italy; ³PhD Program in Neuroscience, University of Milano- Bicocca, Italy

Chemotherapy-induced peripheral neuropathy (CIPN) is a frequent and disabling adverse effect of several anticancer drugs, characterized by paraesthesia, numbness, and dysesthesia, often leading to dose reduction or therapy discontinuation. Despite extensive research, no neuroprotective strategy has yet demonstrated definitive clinical efficacy. However, in vitro evidence suggests the therapeutic potential of Adipose-derived mesenchymal Stem Cell Extracellular Vesicles (ASC-EVs). EVs function as key mediators of intercellular communication, transporting proteins, RNAs, and lipids, and ASC-EVs in particular have been implicated in cellular repair mechanisms. In this study, we employed primary cultures of dorsal root ganglion (DRG) neurons isolated from rat embryos, a well-established model for investigating neurotoxicity, neuroprotection, and post-mitotic neuronal development. We specifically investigated the effects of two clinically relevant chemotherapeutic agents – cisplatin (CDDP, 6 μM) and bortezomib (BTZ, 20 nM) – administered either alone or in combination with a single dose of extracellular vesicles (EVs) for 24 and 48 h. Neuronal viability was assessed by a cellular count at bright-field microscopy, quantifying live cells based on the presence of a birefringent outline. Treatment with CDDP resulted in a pronounced and timedependent decline in neuronal viability at both 24 and 48 h. Coadministration with ASC-EVs significantly mitigated this effect, indicating a strong neuroprotective action. In contrast, BTZ induced a distinct neurotoxic profile, characterized by milder alterations at earlier time points – likely reflecting differences in its mechanisms of action compared with CDDP. Despite these differences, ASC-EVs were also able to counteract BTZ-induced toxicity, further reinforcing their neuroprotective potential. Collectively, these results indicate that the neuroprotective efficacy of ASC-EVs is influenced by both the pharmacological properties of the chemotherapeutic agent and the duration of exposure, suggesting a dynamic, time-dependent interplay between EV- mediated mechanisms and drug-induced neuronal stress. The observed protection is plausibly linked to the modulation of oxidative stress and apoptotic pathways, which are currently being explored. Future investigations will aim to identify the specific molecular mechanism within ASC-EVs responsible for mediating these neuroprotective effects.